DESCRIPTION: The specific aims of this proposal are to (i) assess the adherence capability of the Streptococcus pneumoniae (Spn) serotypes 3,6,14,18,19 and 23 which are capsular types specifically associated with episodes of OM and define the mechanisms involved in this interaction using both in vitro and in vivo models of adherence and adherence inhibition to better understand this critical host-bacteria cell interrelationship. Specifically, the role of lectin receptors of Spn in adherence and invasion will be investigated; (ii) assess the role of Spn neuraminidase in adherence and the pathogenesis of OM; (iii) assess the effect of adenovirus and influenza A virus on Spn adherence, colonization, and OM. These aims delineate steps that culminate in otitis media.